Supercalifragilisticexpialidocious is an English word in the song with the same title in the musical film Mary Poppins. The song was written by the Sherman Brothers, and sung by Julie Andrews and Dick van Dyke. Since Mary Poppins was a period piece set in 1910, period sounding songs were wanted. Supercalifragilisticexpialidocious sounds like popular folk songs "Boiled Beef and Carrots" and "Any Old Iron". Origin Supercalifragilisticexpialidocious is defined as a nonsense word that's used to desc… (More on Supercalifragilisticexpialidocious)